Expect many more mass shootings in the future, because the trend hasn't shown any sign of stopping. Columbine alerted everyone to the danger of mass shootings, but they seem to have only increased in frequency since then.
The day will come one day soon when God Almighty will do away with all the violence in the world, and destroy all the wicked. "Let go of anger and abandon rage; Do not become upset and turn to doing evil. For evil men will be done away with, but those hoping in Jehovah will possess the earth. Just a little while longer, and the wicked will be no more, you will look at where they were, and they will not be there, but the meek will possess the earth, and they will find exquisite delight in the abundance of peace." (Psalms 37:8-11)